Energy-efficient home extensions | Springbok Domestic Build

A vibrant urban construction scene with cranes and buildings under a twilight sky.

Insulated from the ground up

Floors, walls and roofs detailed together

01

Tell us the plan

We talk through the space you want and how you use the house now.
02

Survey and costing

We visit, measure up, and price the build with the insulation specified.
03

Build and hand over

We build to the agreed drawings and walk you through the finished work.

What we build

Extensions, garden rooms and the insulation that makes them work

Single-storey rear extensions

Kitchen and living space added to the back of the house, with floor, wall and roof insulation specified together so the new room performs like the old one.

Two-storey side extensions

Extra bedrooms or a larger ground floor with a matching upper floor. We detail the junction where the new walls meet the existing ones to keep cold bridges out.

Garden rooms and studios

Insulated outbuildings for an office, a workshop or a spare room. They are built with their own heating and ventilation rather than left as a cold shed.

Glazing and door specification

We advise on triple glazing, thermally broken frames and where the windows should sit in the wall to cut heat loss without losing daylight.

Airtightness and ventilation

We seal the shell carefully and fit background ventilation or a heat recovery unit, so a tight extension still has clean air moving through it.

Heating and hot water links

We extend your existing heating into the new space, size the radiators or underfloor loops for the room, and check the boiler can carry the extra load.

How a job runs

From first enquiry to the finished room

Send us the enquiry

You tell us the type of extension you have in mind, roughly what it should cost and where the property is. Drawings or a planning reference help, but they are not essential at this point.

Build, snag and hand over

We build the extension, keep the site tidy, and walk the finished work with you. Any snags are listed and put right before we ask for the final payment.

Practical answers

Planning permission, insulation specs and party walls

These answers cover planning, building control, insulation standards, cost and how we work on a lived-in house.

Do I need planning permission for a single-storey rear extension?

Many rear extensions fall under permitted development, which means no planning application, but the rules limit depth, height and how close you build to the boundary. We check your specific case against the limits before quoting, and if a full application is needed we say so at that point.

How much insulation does a new extension actually need?

Building regulations set the minimum for floors, walls, roofs and glazing, and we build to those figures or better. The exact thickness depends on the construction, so we set it out in the quote rather than quoting a single number that suits every job.

Will a more efficient extension cost noticeably more to build?

Better insulation, triple glazing and an airtight shell add to the build cost, and the amount varies with the size and shape of the extension. We show the difference in the quote so you can see what each item adds and decide where to spend.

Who deals with building control and the inspections?

Either you use the local authority building control service or an approved inspector, and we work with whichever you choose. We notify them at the right stages, arrange the inspections, and keep the certificates together for you at the end.

Can you build while we are living in the house?

Yes, most of our work happens on occupied homes. We plan the noisy stages, keep a route in and out of the house, protect floors along the working path, and leave the site tidy at the end of each day.

Do you handle party wall agreements with neighbours?

Where the work touches a shared wall or excavates near a neighbour's foundation, a party wall award is usually needed. We can point you to surveyors who handle it, and we plan the build around the notice periods.

What customers say

Rooms our customers now live in

We wanted the new kitchen to be as warm as the rest of the house, and it is. They took time over the floor and roof insulation instead of rushing to get the walls up. The whole build ran to the programme they gave us at the start.

Rachel Ainsworth

The quote listed the glazing and insulation separately, so we could see what we were paying for. Nothing appeared later as an extra. They also sorted the building control visits without us having to chase anything.

Daniel Okoro

We stayed in the house throughout the build. They kept the dust down, protected the hallway and told us each week what was coming next. The garden room is now my office and it holds heat through the winter.

Priya Shah

Our side extension needed a party wall award and the builders worked around the notice period without any fuss. They spotted a drainage run under the garden before digging and reworked the design on the spot. The finished room is airtight and quiet.